Comment 35 for bug 28835

This is the output for my 3,5" USB hard disk which has its own power cord:
azrael@laptop:~$ sudo lsusb -vv -d 04b4:6830
[sudo] password for azrael:

Bus 001 Device 006: ID 04b4:6830 Cypress Semiconductor Corp. CY7C68300A EZ-USB AT2 USB 2.0 to ATA/ATAPI
Device Descriptor:
  bLength 18
  bDescriptorType 1
  bcdUSB 2.00
  bDeviceClass 0 (Defined at Interface level)
  bDeviceSubClass 0
  bDeviceProtocol 0
  bMaxPacketSize0 64
  idVendor 0x04b4 Cypress Semiconductor Corp.
  idProduct 0x6830 CY7C68300A EZ-USB AT2 USB 2.0 to ATA/ATAPI
  bcdDevice 0.01
  iManufacturer 56 Cypress Semiconductor
  iProduct 78 USB2.0 Storage Device
  iSerial 100 DEF10000BC41ACB
  bNumConfigurations 1
  Configuration Descriptor:
    bLength 9
    bDescriptorType 2
    wTotalLength 32
    bNumInterfaces 1
    bConfigurationValue 1
    iConfiguration 0
    bmAttributes 0xc0
      Self Powered
    MaxPower 0mA
    Interface Descriptor:
      bLength 9
      bDescriptorType 4
      bInterfaceNumber 0
      bAlternateSetting 0
      bNumEndpoints 2
      bInterfaceClass 8 Mass Storage
      bInterfaceSubClass 6 SCSI
      bInterfaceProtocol 80 Bulk (Zip)
      iInterface 0
      Endpoint Descriptor:
        bLength 7
        bDescriptorType 5
        bEndpointAddress 0x02 EP 2 OUT
        bmAttributes 2
          Transfer Type Bulk
          Synch Type None
          Usage Type Data
        wMaxPacketSize 0x0200 1x 512 bytes
        bInterval 0
      Endpoint Descriptor:
        bLength 7
        bDescriptorType 5
        bEndpointAddress 0x86 EP 6 IN
        bmAttributes 2
          Transfer Type Bulk
          Synch Type None
          Usage Type Data
        wMaxPacketSize 0x0200 1x 512 bytes
        bInterval 0
Device Qualifier (for other device speed):
  bLength 10
  bDescriptorType 6
  bcdUSB 2.00
  bDeviceClass 0 (Defined at Interface level)
  bDeviceSubClass 0
  bDeviceProtocol 0
  bMaxPacketSize0 64
  bNumConfigurations 1
Device Status: 0x0001
  Self Powered

I guess the last line is the thing that you are looking for.